It might not be a great idea to throw stones at glass houses, but no one ever said anything about money. The Urban Glass House, the last residential building designed by the late Philip Johnson, hit the market three months ago and 25 percent of the 40 units are already sold.

Larger units have sold for close to $4 million and a four-bedroom, 2,300 sq. ft. unit just hit the market for $2.95 million.

The 12-story building at the corner of Spring and Washington Sts. on the western edge of Soho endured many incarnations before a final design was selected. After Johnson died last January at 98, architect Annabelle Selldorf was selected to design the buildings interior.